Cryptography – Particular algorithmic function encoding
Patent
1991-08-09
1993-01-05
Swann, Tod
Cryptography
Particular algorithmic function encoding
380 23, 380 50, H04K 100
Patent
active
051777908
DESCRIPTION:
BRIEF SUMMARY
The invention described herein is related in subject matter to application Ser. No. 07/741,520 filed concurrently herewith and entitled: "Method For Generating A Random Number In A System With Portable Electronic Objects, And System For Implementing The Method". Said application corresponds to French application 89.16769 filed Dec. 19, 1989 and PCT application PCT/FR 90/00924. The subject matter of said U.S. application is hereby incorporated by reference.
The invention relates to a method for generating a random number in a data processing system, and to a system for implementing the method.
Random numbers are known and used in data processing systems, particularly when there is a need to perform encoding or encryption of data, for instance before their transmission between two stations connected to one another. The concept of connection should be understood broadly, and applies both to stations some distance from one another, connected by at least one transmission line, and to stations incorporated in the same housing or quite close to one another.
A method for data encoding or encryption comprises causing one of the stations to generate the random number, and then performing an operation of encryption of data before the data travel over the transmission line, with the aid of an encryption function which may be more or less complicated; as input parameters, this function uses the data, the random number, and an encryption key, among other elements.
In such a case, an encryption function is memorized in each of the stations, for example in the form of an algorithm recorded in an encryption module, and for a station receiving an encrypted message or information to be capable of deciphering it, it must include a deciphering module that makes it possible to perform an operation on the encrypted message it receives, so that it can retrieve the original message.
It is understood that the station in which the deciphering is performed must have knowledge of the random number, and generally of all the parameters used for the encryption.
Numerous patent applications in the name of the assignee of the present invention or mention systems that implement data encryption and deciphering algorithms, and show various ways of using random numbers, particularly in systems with microcircuit cards, also known as memory cards and/or microcalculator cards, depending on the complexity of the circuits they include. Once such published application is French application 2 601 535.
The advantage of using a random number to encrypt data or information is obvious: The same encrypted datum with different random numbers produces a different encryption outcome, so that a defrauder finds it difficult to simulate beforehand the outcome of the encryption.
More or less complex solutions, depending on the degree of security or conditions of access that it is desirable to assign to the system, are conceivable.
In these information processing systems, the term random number is generally used in fact to designate the outcome of calculation performed on various parameters, which may for instance be contained in certain memory zones.
As a result, if the parameters used for calculating a random number prove to be identical in two different calculations, then the outcome of these two calculations is the same.
Thus if a skilled defrauder could successfully determine what the parameters used to generate the random number are, and could thus be capable of determining in advance what the next random number calculated would be, then he could determine in advance what the outcome of the encryption applied to an already-encrypted datum would be.
This is why the likelihood that the same random number would be used repeatedly must be reduced as much as possible, so as to limit the risk of fraud as much as possible.
Hence in systems with electronic microcircuit cards, random numbers are used to encrypt the data that are to pass either locally or between the memory or the microcircuits on the card and the terminal to which it is connected, or between the car
REFERENCES:
patent: 4544833 (1985-10-01), Ugon
patent: 4807288 (1989-02-01), Ugon et al.
patent: 4825052 (1989-04-01), Chemin et al.
patent: 4907270 (1990-03-01), Hazard et al.
patent: 4951247 (1990-08-01), Kruse et al.
patent: 4965828 (1990-10-01), Ergotti, Jr. et al.
patent: 4974193 (1990-11-01), Beatelspacher
Computer Network & ISDN Systems, vol. 14, Nos. 2-5, 1987, pp. 389-395; Ph. Van Heurck "TRASEC: National Security System for EFTs in Belguim".
Bull CP8
Swann Tod
LandOfFree
Method for generating a random number in a data processing syste does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for generating a random number in a data processing syste, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for generating a random number in a data processing syste will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2396603